multi-tier provisioning strategy

[kvenkatachala333]

I have implemented the Spot to On-Demand waterfall strategy for the h4d-vm integration test.

1. tools/cloud-build/find_available_zone.sh

• Added ENABLE_SPOT_FALLBACK environment variable check.
• Validates zones against a list of provisioning models: ["SPOT", "STANDARD"] if fallback is enabled, otherwise just ["SPOT"].
• Exports PROVISIONING_MODEL on success to indicate which model succeeded.

2. tools/cloud-build/daily-tests/builds/h4d-vm.yaml

• Enabled ENABLE_SPOT_FALLBACK=true.
• Dynamically sets provisioning_model in the blueprint using the exported PROVISIONING_MODEL variable.
• Sets enable_spot=false for Ansible if the provisioning model is STANDARD.
  Note: Ensure $$PROVISIONING_MODEL and $$SPOT_VAR are used in h4d-vm.yaml to prevent Cloud Build from attempting to substitute them as build variables.

[gemini-code-assist]

Summary of Changes

Hello @kvenkatachala333, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a robust multi-tier provisioning strategy for integration tests, significantly improving their resilience and cost-efficiency. By first attempting to provision resources using Spot VMs and gracefully falling back to On-Demand VMs when necessary, the system ensures that tests can reliably acquire the required infrastructure while minimizing operational costs. This change centralizes the provisioning logic, making it more adaptable to varying cloud resource availability.

Highlights

• Waterfall Provisioning Strategy: Implemented a new provisioning strategy for integration tests that prioritizes cost-effective Spot VMs and automatically falls back to On-Demand VMs if Spot instances are unavailable.
• Dynamic Blueprint Generation: Introduced a new helper method, generate_blueprint_with_spot_config, to dynamically create temporary blueprint files with specified Spot VM configurations (enabled or disabled).
• Tiered Deployment Logic: The deploy method was refactored to execute a two-tier deployment process: first attempting with Spot VMs, and upon failure, cleaning up any partial deployment and retrying with On-Demand VMs.
• Error Handling and Cleanup: Enhanced error handling in the deployment process to catch failures during Spot VM provisioning, trigger cleanup of failed deployments, and proceed with the fallback On-Demand strategy.

Changelog

• tools/python-integration-tests/deployment.py
  • Added copy and tempfile imports for blueprint manipulation.
  • Introduced generate_blueprint_with_spot_config method to create temporary blueprints with configurable Spot VM settings.
  • Refactored deploy method to implement a two-tier (Spot then On-Demand) provisioning strategy with fallback logic.
  • Incorporated error handling and cleanup (destroy) calls within the deploy method for failed provisioning attempts.

Using Gemini Code Assist

The full guide for Gemini Code Assist can be found on our documentation page, here are some quick tips.

Invoking Gemini

You can request assistance from Gemini at any point by creating a comment using either /gemini <command> or @gemini-code-assist <command>. Below is a summary of the supported commands on the current page.

Feature	Command	Description
Code Review	/gemini review	Performs a code review for the current pull request in its current state.
Pull Request Summary	/gemini summary	Provides a summary of the current pull request in its current state.
Comment	@gemini-code-assist	Responds in comments when explicitly tagged, both in pull request comments and review comments.
Help	/gemini help	Displays a list of available commands.

Customization

To customize Gemini Code Assist for GitHub experience, repository maintainers can create a configuration file and/or provide a custom code review style guide (such as PEP-8 for Python) by creating and adding files to a .gemini/ folder in the base of the repository. Detailed instructions can be found here.

Limitations & Feedback

Gemini Code Assist may make mistakes. Please leave feedback on any instances where its feedback is incorrect or counter productive. You can react with 👍 and 👎 on @gemini-code-assist comments. If you're interested in giving your feedback about your experience with Gemini Code Assist for Github and other Google products, sign up here.

You can also get AI-powered code generation, chat, as well as code reviews directly in the IDE at no cost with the Gemini Code Assist IDE Extension.

Footnotes

1. Review the Privacy Notices, Generative AI Prohibited Use Policy, Terms of Service, and learn how to configure Gemini Code Assist in GitHub here. Gemini can make mistakes, so double check it and use code with caution. ↩

[kvenkatachala333]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a multi-tier provisioning strategy, falling back from Spot to Standard VMs for the h4d-vm integration test. The changes look good and correctly implement the fallback logic in both the zone-finding script and the Cloud Build configuration. I have a small suggestion to improve clarity in the shell script. Overall, a solid implementation of the new strategy.

[simrankaurb]

/gemini review

[gemini-code-assist]

Code Review

This pull request introduces a fallback strategy from Spot to Standard VMs for the h4d-vm integration test, which is a valuable improvement for test reliability. The changes in find_available_zone.sh correctly implement the core fallback logic. However, I have some suggestions to improve maintainability and robustness. In add-instance-labels.yml, several redundant conditional checks have been added. Finally, the find_available_zone.sh script has become quite complex and would benefit from refactoring to improve readability.